US 2013/0153772 A1 discloses an opto-electronic module and devices comprising the same. A wafer stack is formed by a baffle wafer, an optics wafer, a spacer wafer and a substrate wafer. The optics wafer comprises transparent elements forming passive optical components between non-transparent portions. The transparent elements are aligned with openings in the baffle wafer and in the spacer wafer and with emission and detection members arranged on the substrate wafer.
WO 2009/076788 A1 discloses a method for fabricating an integrated optical device by stacking a top wafer comprising lenses on a further wafer comprising further functional elements, and separating the wafer stack into a plurality of devices. A sunshade plate comprising a plurality of through holes is arranged on the top wafer, so that the through holes, the lenses and the functional elements of the further wafer are aligned according to optical axes.
U.S. Pat. No. 8,378,496 B2 discloses a semiconductor device comprising an interlayer connection formed by a contact-hole filling of a semiconductor layer and a metallization of a recess in a reverse-side semiconductor layer.